Surfactant molecules

A surfactant or surface active agent is a substance that, when dissolved in water, gives a product the ability to remove dirt from surfaces such as the human skin, textiles, and other solids. Detergents and cleaning products depend upon surfactants for their cleaning. Surfactants are often referred to as the washing actives, “engine” and workhorse of the detergent system.

  • Function and benefits

    What is its function and benefit?
    The main function of a surfactant is cleaning. They wet the fabrics and soils and so allow the removal of soils and dirt. They suspend a whole range of stains and dirt (particulate, grease, body soils, cosmetics).

    How does it work?
    Surfactants work by:

    • Breaking up & removing stains
    • Suspending soil
    • Preventing redeposition onto fabrics.

    Each surfactant molecule has a hydrophilic (water-loving) head that is attracted to water molecules AND a hydrophobic (water-hating) tail that repels water and simultaneously attaches itself to oil and grease in dirt. These opposing forces loosen the dirt and suspend it in the water. The mechanical agitation of hand washing or washing machine helps pull the dirt free. (Ref: Wikipedia)
    Surfactants are often referred to as wetting agents and foamers. Surfactants lower the surface tension of the medium in which it is dissolved. By lowering this interfacial tension between two media or interfaces (e.g. air/water, water/stain, stain/fabric) the surfactant plays a key role in the removal and suspension of dirt (anti-redeposition). The lower surface tension of the water makes it easier to lift dirt and grease off of dirty dishes, clothes and other surfaces, and help to keep them suspended in the dirty water. The water-loving or hydrophilic head remains in the water and it pulls the stains towards the water, away from the fabric. The surfactant molecules surround the stain particles, break them up and force them away from the surface of the fabric. They then suspend the stain particles in the wash water to remove them.
    For a more in-depth understanding of surface tension, see:

  • Chemical structure and composition

    Hydrophobic tail and hydrophilic head

    A surfactant consists of a hydrophobic (non-polar) hydrocarbon "tail" and a hydrophilic (polar) "head" group.
    This appearance is key to its behaviour. The dirt-loving or hydrophobic tail absorbs the oil and grease in dirt and stains while the water-loving part will bring and suspend the soil into the wash solution so that it can be removed.

  • Product / Category: where is it used?

    Various types of surfactants are commonly used in detergents in which they are a basic cleaning active. They can be present at low levels (<5%) as well as in considerably higher levels (e.g. 20-30%) in concentrated products. In addition to their leading role in laundry and light duty formulations, surfactants are used to some degree in most other household cleaning and washing products. They are the base of most liquid hard surface cleaners. Relatively small amounts of surfactant are usually included in powdered hard surface cleaners, cleansers, and automatic dishwasher detergents. Specialized surfactant applications include the use of cationic quaternary ammonium compounds to provide deodorizing and disinfecting action, while nonionic wetting agents are available for adding to the last rinse in automatic dishwashing to provide better draining of rinse water. (Ref: SDA science)
    Surfactants play an important role as cleaning, wetting, dispersing, emulsifying, foaming and anti-foaming agents in many practical applications and products, not only including detergents, but also fabric softeners, emulsions, paints, adhesives, etc. (Ref: Wikipedia)
    Biosurfactants are surface-active substances synthesised by living cells; they are generally non-toxic and biodegradable. (Ref: Wikipedia)
  • Ingredient safety and information

    Many detailed HERA risk assessments have been carried out for several different widely used surfactants, e.g. Linear alkyl benzene sulphonate (LAS), Alkyl sulphate (AS) or Alcohol Ethoxysulphates (AES). Surfactants are very well studied, risk-assessed and documented.
    Generally, the environmental risk characterisation as expressed by the PEC/PNEC ratio is below 1 for all environmental compartments, which means that ecological risk of surfactants is judged to be low. The absence of environmental concerns can be demonstrated for many surfactants used today.
    Similarly, the human health risk assessments have shown that the use of the most widely used surfactants in household laundry and cleaning detergents are safe and that consumer exposures are not of concern.
    For ingredient safety and information of the different surfactants, please refer to the specific Glossary entries.

  • References

The Head Line


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